Tennis racket



June 1932- R. H. ROBINSON TENNIS RACKET Filed Feb. 25, 1927 JZZZLIS.

gv/vnlv": Roy H. ROEzJnsorg M 1 Patented June 14, 1932 ROY E. ROBINSON, OF CHICAGO, ILLINOIES TENNIS EACKET Application filed February 25, 1927.

ing by the frame and also the use of av bridge piece in the throat portion of the frame, as well as the mounting of the stringing and adjustment of the frame for the purpose of tightening the strings or relieving them, especially at the point where the stringing is subject to the greatest force or strain of impact and in such a manner as to resist the extra tension which comes on the longitudinal center of the racket, tending to elongate the "acket frame at the center.

A further object of the invention is to provide a racket possessing all of the advantages disclosed in the constructions of my prior Patent No. 1,470,878 of October 16, 1923, and my ce-pending application Serial No. 680,956, filed December 15, 1923, as well as embodying other features which improve the racket and simplify the construction, and thus permit manufacture more expeditiously and with greater economy.

It has been found in practice that silk or gut string cannot be used with metal frame rackets as now produced because the metal quickly cuts the stringing or gut, except as shown in my prior devices above referred to. Some metal rackets have been made which were strung with wire, but these do not possesses the resiliency of gut, and even the wire soon breaks if no provision is made for obviating the cutting thereof by the metal at the holes or passages where the stringing passes through the frame. hese metal frames are made of light gauge metal tubing which is punched for the tubing and then bent into proper form. Thepunched holes are made as smooth as possible but the strings come into contact with the edges of the metal at the holes and are cut thereby. This cutting is accelerated or augmented by the mov- 1 the strings when the racket is in use. The in'esent invention improves the racket construction by providing a filler strip in the tube which not only acts as a cushion for the swings at the passages or holes so as to prevent t'he exposure of the edges of the metal Serial No. 170,777.

at the passages and contact of the strings therewith, resulting in cutting of the strings, which is hastened by the rubbing of the strings thereagainst, but also comprises vision absorbing means ail sound deadener, so that the noise and vibration will not be transmitted down into the handle and prove lisadvantageous in the use of the racket. In my improved racket the advantages of the metal frame are fully retained, but the cutting of the string is eliminated, thus permitting gut or silk, and especially the former, to be used as well, if not better, than with a wooden frame racket, without the serious ob jections noted.

Another object of the inv ion is to provide for the adjustment of t .e frame as hv means of a turnbuckle connection so that the frame may be expanded or contracted at throat of the racket to vary its size or circumference at will, thus tights? or relieving them.

Another object of the invention is to provide a construction in which the bridge piece is entirely eliminated and the Stlil'lgSDYUlli'dil in a novel manner, nrovision being made for doubling the strings at the center or 1 crossing and anchoring them at opposite sides so as to strengthen the racket at the point of greatest force or strain of impact, thus permitting the double set of strings to be ened directly and at the point in the racket where the greatest ten Y o be had. The crossed or double resist the extra tension which comes on the longitudinal center of the racket and the tendency of the t Lillie igin 4 i118 many other oo ecis and advantages of my invention will be etter understood by reference to the following specification when considered in conne ion with the acconipan; ing drawing illust ating certain selected cmbodiments thereon, in which Fig. 1 is a plan view of a racket embocying the improvements.

Fig. 2 is an enlarger longitudinal seetional view of a portion of a complete frame.

Fig. 3 is a sectional view taken on the line 83 of Fig. 2.

Fig. is a fragmentary plan view SliOK another form of frame construction and stringing arrangement together with means for expanding or contracting the frame for tightening or relieving the strings from the throat of the racket or shank thereof, and

Figs. 5, 6, and T are fragmentary plan views of modified constructions.

Referring to the drawing in detail and particularly to Figures 1 to 3 inclusive, the racket comprises a frame 10, handle 11, and stringing 12. The frame in the present instance comprises a tube of metal such as nickel steel, or similar ferrous alloy, or the metal tubing may be of nickel or Monel metal and is bent into substantially oval form to provide a frame of the desired shape. The ends of the tubing are turned outwardly as indicated at 18 and these ends are extended into the handle as indicated at 1 1 to provide a shank of the necessary strength. They are extended through a ferrule and may be in contact or spaced apart as desired. The ferrule has a lip 16 where the ends 14 extend therethrough or a pair of lips or flanges surrounding the openings at the top of the ferrule at its closed end, according to whether the portions 13 and l i are in contact or spaced apart. As shown in Figure 1, the portions 13 and 14: are in engagement and they may be rein forcec by a brazed joint 1'? from the ferrule to the point where they branch outwardly to form the frame proper. Of course, instead of brazing these parts together, they may be welded, spotwelded, soldered, or otherwise joined.

Heretofore, the portion 13 of the tube or metal tubing of steel or the like forming the frame at the throat of the racket was provided with a strut or spreader commonly referred to as a bridge piece and which was understood to be necessary to give the de sired strength or rigidity to the frame. This reinforcing bridge piece was usually brazed or welded into position and the oper tion incident thereto is very expensive, but I found in practice that it is not only unnecessary but can be entirely eliminated with decreased cost of production and greater efiiciency and economy in manufacture and at the same time provide a racket frame which possesses more than ample strength. Of course, the handle may be of wood or other material and the metal ferrule 15 employed or omitted, as found most desirable to suit the desires of different user Where the metal ferrule is employed, it envelope and supports the forward end of the handle and helps to strengtln en the anchoring of the shank of the frame therein.

In my improved construction of metal tubing or tube 10 forming the racket frame, the same is either completely or partially filled with non-metal substance or filler 18 preferably in the form of a strip which partially fills the tubing. t may engage the opposite sides of the tubingthat is, the lateral sides as distinguished from the inner and outer sides and may be formed of any number of 1 variety of substances or materials. The filler, however, may be one that will not absorb moisture and consequently will not Warp, such as bakelite, or may be ordinary fiber, hard fiber, leather, raw hide, or combinations thereof, the tiller being of a resilient or compressive nature, as distinguished from metal which will not give to the stringing, in order to cushion the stringing and prevent breaking or cutting thereof. This non-metallic cushioning material may be also of a plastic molded mass, such as vulcanized fiber thoroughly impregnated with a combination of phenol and formaldehyde and then hardened by heating, although it is not essential to have such high compressive strength and relatively high tensile strength as this material has. In any event, the non-metallic cushioning or fibrous substance filling strip will serve to effectively absorb vibrations and dampen or deaden sound, so that neither will be transmitted down into the handle, thus obviating one of the objections to metal tennis rackets as heretofore constructed.

The filled tubing may be manufactured in a variety of ways, but in Figures 2 and 3 of the drawing the filler strip 18 is driven or drawn into the round or oval tubing either before or after the same is shaped, but preferably before the tube is bent to form the frame. The tube is punched for the stringing either before or after the filler is placed in the tube, although the filler is preferably drawn into the tube after the tubing is drilled or punched. In the first punching operation a series of oppositely disposed relatively large holes 19 are punched in the metal shell and when the filler is inserted, the edges of the holes are pressed into or against the filler. This causes the tube to assume a somewhat oval cross-section if desired, although the tubing may be rolled into this form. The inwardly turned edges 20 of the metal shell at the holes or openings 19 produced by the punching are forced into the filler or merely brought into contact therewith as indicated, to keep the strings out of contact with the shell or edges thereof at the passages, thereby preventing the strings from being cut by such contact where the strings are looped around the passages as indicated at 21. The filler is thus permanently embedded in the metal tubing and has passages 22 drilled, stamped, or otherwise formed or molded therein to receive the strin -s and project beyond the edges or to the faces of the metal at the edges 20. This provides a cushion on which the strings bear, giving the necessary resiliency and shock or vibration absorbing and sound deadening qualities which would not otherwise be provided in a hollow metal tube without a filler, forming the frame of the racket. Of course, the edges of the small holes are preferably slightly rounded or chamfered to provide a round bearing surface for the strings and the punched tube may be passed between compression rolls to further flatten the frame or tubing composing the same, and in order to further force the punch-hole edges into the filler either preceding or following the drilling of the filler. The small holes in the filler may be obviously provided before it is inserted in the metal tubing. This is preferable where the filler is composed of hard fiber or the like.

After the filler is in position the ends l i are anchored in the handle and, as previously stated, may be brazed or otherwise joined along the shank portion as indicated at 17 or simply disposed in contact or left spaced apart as shown in the other figures of the drawing. The stringing 12 is mounted as shown in F1 gure 2 and the strings 23 at either side of the center of the frame or throat thereof are extended in opposite directions or otherwise, as will be later described.

In the construction shown in Figure l of the drawing, the portions ll are shown spaced apart and the ferrule has spaced lips or flanges 24 receiving the shank portions. it is optional in this form to provide the throat of the racket with a turnbuckle 25 engaging screws or threaded stems 26 which may be anchored in opposite sides of the shank as indicated at 27 by threading, welding, riveting or other fastening means so as to provide means for expanding or contracting the frame of the racket at the throat to expand and contract the circumference of the racket at will and thus tightening the strings or relieving them. In this construction the threads of the turnbuckle or screw-headed portions are located between the two spaced portions or tubes of the shank adjacent the throat of the frame and, if desired, the stringing, instead of being arranged as shown in Figures l and 2, may have reinforced central stringing 28 crossing at the point 29 and branching to opposite sides as indicated at 30 to run through the passages independently of or jointly with adjacent strings and having the ends suitably anchored. One or more strings of this kind'that is, double strings may be employed, the members of which anchor to opposite sides of the frame above the turnbuckles. It will be seen that with this construction, in the expanding of the racket this will make a direct tightening of these double strings which may be twisted about each other throughout their entire lengths, or rather the entire length of the racket frame at the point in the racket where the stringing or gut is exposed to the greatest force or strain of impactthat is, where the greatest tension is to be had. Double strings will also tend to resist the extra tension which comes on the longitudinal center of the racket, the tendency of the tennis racket being to elongate at the center as the stringing is made tighter. In the construction shown in Figure 5, the shank portions 14 are preferably brought closer together at the throat as indicated at 31that is, converge from the ferrule 15 to the throat portion or diverge in the opposite direction, although this divergence need not be excessive. In this construction the turnbuckle is designated at 32 and has threaded portions or screws 33 which engage threaded sleeves or openings 34 within the tubing at either side in a metal reinforcement, such as 34, in which the threads are provided. These metal reinforcements may be inserted in the tubing in the preferred construction or formed as separate pieces welded or otherwise secured or anchored therein. The stringing in this form may be as shown in Figure 1 or the strings at the center may cross or be twisted or entwined around each other at the point of crossing onlyorthroughout their lengths as heretofore described in connection with Figure d.

In Figure 6, another form is shown in which the turnbuckle is of the same construction as illustrated in Figure l and designated by similar reference characters, the turnbuckle in each instance having openings 35 for the insertion of a pin or key for turning the same to tighten or relieve the strings by the expansion or contraction which thus results. However, in this form the threads of the turnbuckle lie between the tubing and the shank portions of the tubing are curved outwardly in convex formation as indicated at 36 and in opposite directions so as to bring the parts '37 closer together to form a contracted portion to correspond to the part 31 but giving additional spacing for the turnbuckle by reason of the outwardly curved or bowed portions 36.

In Figure 7 another mounting for the turnbuckle is shown in which the turnbuckle proper is also an internally threaded member as distinguished from the member 32 in Figure 5, which is simply a central annular flange or enlargement on the screw having the right hand and left handed or oppositely threaded ends 3 engaging the similarly threaded inserts 34. in this form. the thread ed shank portions are designated at 38, and instead of being anchored in the opposite tubing by extending through openings therein or the like. the turnbuckle lies between the tubing and the threaded portions are anchored or secured to the spaced shank portions by means of collars 39 disposed around the tubing and suitably brazed, Welded, or otherwise anchored thereto and in a manner which serves to strengthen rather than weaken the frame at these points.

Instead of inserting the filler in the unpunched tube, which latter may be made of astrip turned into shape and thenpunching ing a filler of a thickness to allow it to be pushed into the tube between the protruding edges of the punched holes. The tube may then be compressed between the rollers or otherwise to cause the edges of the metal at the openings to be embedded or placed in contact with the filler.

It will be evident from the foregoing de scription that the stringing in my improved socket is held away at all times from the metal edges by the filler and cannot be cut thereby. The metal bearing surfaces are smooth and rounded. The metal tube or shell ma be made of thin steel, aluminum, alloy, nic e1, or any other material possessing the necessary strength and lightness. The frame also may be of other suitable material or construction, reinforced or not, such as a nonmetal substance. For instance, a plastic molded mastic in the form of a vulcanized fiber thoroughly impregnated with a combination of )henol and formaldehyde and then hardened y heating, wood, or the like, possessing the necessary compressive and tensile strength, without the bridge piece or filler at the throat portion, but with the shank portions spaced apart or in contact and anchored to the handle or extended to form the same, and all the stringing secured directly to the sides of the frame at the throat instead of to the customary bridge or filler.

1 am aware that the frame construction may be materially varied without departing from the principles of the invention, and I reserve the right to make all such changes as fairly fall within the scope of the following claims.

I claim as my invention:

1. In a tennis racket, a frame comprising a tubular metal shell, the ends of the shell being bent outwardly to form a throat portion, a handle mounted on said ends, stringing in the frame extending partially into the throat portion, and means between said shell ends below said throat portion for spacing or contracting the same, the throat defining shell portions being mutually unconnected to permit independent flexing and torsion thereof under playing strains.

2. In a tennis racket, a frame comprising a tubular metal shell, the ends of the shell being bent outwardly to form a throat portion, a handle mounted on said ends, the longitudinal stringing being entirely secured to the shell and an adjustable turnbuckle connection for said shell ends and located between the throat portion and the handle to tighten or relieve the stringing, the throat defining shell portions being mutually unconnected to permit independent flexing and torsion thereof under playing strains.

3. In a tennis racket, a frame comprising a tubular metal shell, a non-metallic filler within the shell, the ends of the shell being bent outwardly to form a throat portion, a handle mounted on said ends, stringing anchored in the frame and extending through openings in the frame and filler in contact with the latter, the longitudinal stringing being entirely secured to the shell and an adjustable turnbuckle connection for said shell ends and located between the throat portion and the handle to tighten or relieve the stringing.

4;. In a tennis racket, a metallic frame having converging portions defining a throat, shanks forming continuations of said converging portions, the shanks being brazed together below the throat and holding the shanks rigidly against collapsing inwardly and torsional displacement in play, the frame portions defining the throat being mutually unconnected to permit independent flexing and torsion thereof under playing strains.

5. In a tennis racket, a metallic frame, the ends of the frame being directed outwardly in converging relation to form an open and unobstructed throat, and shanks, the shank portions entering the handle in spaced relation, and a metal tie connecting the shanks and located between and independent of the handle and throat in the plane of the stringing.

6. A tennis racket comprising a tubular frame in which the customary bridge at the throat is omitted, the stringing being secured directly to the sides and shanks of the frame members, the opposite sides of the tube being joined by a cross tie located below the throat and substantially in the plane of the stringing and attached to the outside of the tubing, the frame portions defining the throat being mutually unconnected to permit independent flexing and torsion thereof under playing strains.

7. In a tennis racket, a frame comprising a tubular metal shell, the ends of the shell being bent outwardly to form an unobstructed throat portion, a handle mounted on said ends, stringing in the frame extending partially into the throat portion, and an adjustable turn-buckle connection between the shell ends and located between the handle and the unobstructed throat portion to tighten or relieve the stringing.

8. In a tennis racket, a frame comprising a tubular metal shell with the ends turned outwardly to define a throat and also form shank portions, the throat of the frame being freely open and unobstructed in the plane of the stringing and the frame ends being anchored together by means of a turnbuckle below the stringing holes and connecting the shank portions independently of the throat defining portions of the frame.

9. In a tennis racket, a metal frame having converging portions defining an open throat, shanks forming continuations of said converging frame portions, and metallic shank-connecting means in the plane of said frame and located below the throat and connecting said shanks and holding them rigidly against collapsing inwardly and against torsional displacement in play, the throat defining frame portions being mutually unconnected to permit independent flexing and torsion thereof under playing strains.

10. In a tennis racket, a metallic frame having converging portions defining an open throat, shanks forming continuations of said frame portions said shanks contacting for a substantial portion of their length below said throat, said shank portions below the throat being brazed together for holding them rigidly against collapsing inwardly and against torsional displacement in play, the throat defining frame portions being mutuaL ly unconnected to permit independent flexing and torsion thereof under playing strains.

11. In a tennis racket, the combination as defined in claim 10, a handle receiving said shanks, and a metal ferrule fitted securely to said handle and having a single opening of smaller diameter than the major portion of said ferrule and snugly seating said shanks.

ROY H. ROBINSON. 

